We are studying the defective differentiation known to characterize human leukemia populations by: Characterizing the genetic mechanisms underlying regulation of expression of fetal and embryonic programs of globin gene expression in leukemia cells, as well as the decreased levels of alpha globin gene expression seen in patients with acute myelogenous leukemia, by use of somatic cell hybrids and the techniques of molecular biology. We are also studying the changes in mRNA and proteins in the cytoplasm during commitment to myeloid or monocyte differentiation induced in the HL60 cell line by the addition of dimethyl formamide or phorbol esters. Finally, we are studying the regional localization of human alpha globin genes on human chromosome 16 to determine if this gene is closely linked to an unstable region known to exist on this chromosome.